Synthetic oil

I’ve switched to synthetic oil in all my vehicles. They run quieter and smoother but I seem to burn more oil or it disappears somewhere more quickly then the standard. I’ve also been told that it has a detrimental effect on gas mileage. So- what is your take on synthetic vs standard oil?

Synthetic oil lubricates differently than conventional, which is not necessarily better for a car that doesn’t require it. Because of its different molecular structure, synthetic oil can flow places that conventional oil can’t, and so because of this it can sneak past rings and seals that conventional can’t and so sometimes you see higher oil consumption.

Depending on how much oil is disappearing, I’d probably switch back to conventional for the cars that seem to use more synthetic oil. That stuff is expensive!

Also, I’ve never heard of it leading to lower gas mileage. Usually the claim is the opposite.

i drive a 99 volvo s80 and i recently switched to synthetic oil. i absolutley love it! a guy at the local jiffy lube suggested it(HE DROVE A 00 AUDI A4)and after talking it over with my main mechanice at a local volvo dealership (GOT TO KNOW SOMEONE ON THE INSIDE) i went for it. my gas mileage has been always great in my volvo (178,000mi & counting) an i would say i havent had anything but great succsess with the synthetic oil. WILL NEVER GO BACK TO CONVENTIONAL! and oil changes are few and far between (5000 for synthetic). which brings up a question: HOW MUCH WAS THAT GUY MAKING TO BE DRIVING AN AUDI WORK FOR JIFFY LUBE?? hummm???.. lol.

I have used Mobil 1 Synthetic in all my vehicles since 1986. My cars have always loved it and so I love it. I also changed out the ATF to Mobil 1 Synthetic ATF in my latest vehicle and I am so glad I did. Don’t understand the mpg reduction report. Maybe you should put the question to the engineers at the website of the syntheic oil you are using.

If you want to learn about oil, is a must-read.

I like GreasyJack’s comment about synthetic is not necessarily better for a car that doesn’t require it. You’ll find the “placebo effect” looms large with the synthetic oil topic, or rather “I’m paying lots of money for this stuff so it has to be much better.”

Millions of drivers continue to get excellent results from dyno oil and they’re saving lots of money.

And the list of cars that don’t “require” synthetic oil is where? Any vehicle can benefit from synthetic oil. What I find is, people who never used synthetic lubricants such as Mobil 1 seem to make themselves out to be the most qualified to dismiss it. Corvette, Viper, Porsche, Mercedes recommend it for good reason. If expensive cars will benefit from it any car can benefit from it. And, at $22.00 for 5 quarts that will last 15,000 miles between changes is a better deal than 3000 mile oil that can do things synthetic oil can’t - like, wear out, gum up, and varnish cylinder walls, etc. Besides, people who use synthetics are decreasing the demand for Saudi oil. So, it’s a win for everybody. More FACTS at the ExxonMobil site.

I must respectfully disagree with your logic.

First, because high performance engines benefit from it does not mean that all engines will benefit. Engines that place higher than normal temperature stresses on oil, especially those with turbochargers, can benefit because synthetic withstands the higher temperatures better. But regular unturbocharged engines don’t cause this damage to oil…except in the rare case of a design problem like the Camry V6 engines had.

Second, all oils are subject to the same dilution and contamination from blowby and particulates whether synthetic or not. To go 15,000 miles between changes because you’re using synthetic extends the time between oil changes…but my goal is rather to extend the life of the engine. There is no way I’d go 15,000 miles between changes. IMHO to do so is folly.

In over 40 years of car ownership, three winters of it in sub zero weather up to -40F ambient, including having driven sone engines hundreds of thousands of miles, I’ve never worn an engine out. And I’ve used only dino.

Further, while I’ve seen lab tests touting better lab performance from synthetic, I’ve never seen a single study that corrolates synthetic directly to longer engine life.

Bottom line: if the owner’s manual recommends synthetic, you should use it…but do not use it to extend the time between oil changes. If the owner’s manual only references the typical weights, specs, and ASE & API badges then you can use either…but do not use synthetic to extend the time between oil changes.

Agree with mountainbike; synthetic oils are for special engines and extreme applications in normal engines. It’s a myth that synthetics allow you to greatly extend the oil change interval, unless the additive package has been boosted, such as in a LONG DRAIN version of Mobil 1. Even with that I would not go 15,000 miles unless I was doing only highway driving at moderate speed and load.

The common misconception is that just because an oil is expensive it will last longer, is hard to kill.

The longer engine life (compared to what it would be otherwise) will only happen if the operating cosnditions are severe, in terms of temperature, load, etc.

Under normal driving conditions for a non-turbo engine any mineral oil meeting the spec will do. I have been driving since 1954 and have owned cars since 1958, and the last time I did engine work was 1964. I have never since got rid of a car because the engine failed or was worn out. Most of the time have used normal “dino” oil, but have used synthetic during the cold seasons in the last 15 years or so.

I’ll have to disagree here also. I used Mobil 1 synthetic for high milage on my 1500 Ram and after 3000 mile all I got out of it was pure sludge. It almost ruined my engine. I will never use anything but Penzoil conventional or Syntec again.

I have tried using synthetic oil in my machines. I see no benefit in fuel economy, noise, or smoothness. I agree with the assessment that with cars that don’t require synthetic oil, using synthetic oil to extend your oil change interval is foolish. It costs more and it extends the intervals between other valuable services, like checking the other fluids, the air filter, the CV boots, etc.

Our 08 and 09 GM cars both require synthetic oil per the owner’s manuals. I suspect that this is so for at least 4 reasons:

  1. Both, one a DOHC V6 and the other, a DOHC 4 cylinder may need the thinner 5W-30 synthetic to adequately lubricate the cam chain when very cold as well as when hot.
  2. Prevent too large of a slug of unfiltered oil getting through the bypass valve when very cold in the very tiny oil filters being used now.
  3. Better gas mileage.
  4. Using the oil change time calculator, we are headed for at least 12,000 miles to the first oil change on the 09. At around 5 bucks per quart at 12k change compared to around 2 bucks per quart of conventional oil changed at 3000 miles as was my old routine, the synthetic is more economical. If you say to change conventional oil at 5K miles then it’s pretty much equal in cost.

Neither car uses any oil according to the dipstick reading.

In the mid 1960s Chevron U.S.A was the first to market and produce a complete range of 100% synthetic Polyalphaolefins based lubricants, which began to be marketed as a substitute for mineral oils for engine lubrication. Although in use in the aerospace industry for some years prior, synthetic oil first became commercially available in an American Petroleum Institute (API)-approved formula for automobile engines when standards were formalized for synthetic-based lubricants.

Other early synthetic motor oils marketed included “The Original Syn!” by SynLube in 1969, NEO Oil Company (formally EON) in 1970, which were dibasic acide esters, or diesters, and polyol esters-based synthetic lubricants. In 1971 All-Proof, now called Red Line, introduced a synthetic oil, followed fourth by Amsoil who packaged and resold a diester-based 10W40 grade from Hatco[8] in 1972, and then Mobil 1, introduced in North America in 1974 (with a PAO-based 5W20 grade).

It might be helpful to know the age and miles on these vehicles.

I use synthetic oil in my higher value vehicles. In my vehicles that consume a little oil, I use regular oil for the oil changes, but I save the used synthetic oil from the other vehicles and use it as makeup oil in the oil burners/leakers. It has been my experience that as the ratio of used synthetic to conventional increases, the rate of consumption decreases, except with Royal Purple.

The Mobil one and Castrol Syntec oils get changed at 7500 miles and they work better as make up oil than fresh conventional oil. The Royal Purple that my son uses gets changed at 3-5k miles but doesn’t seems to increase oil consumption.

My only oil burner right now is a 2002 Saturn with 201k miles. It burns off the first quart after an oil change at about 2000 miles. If I top off with Mobil One or Syntec, then next quart is needed about 2500 miles later, then I’m good up to the next oil change. If I top off with the Royal Purple, the the next top off is needed 1500 miles later and then again in another 1500 miles. But the top off oil is free.

The last oil user was an old Toyota. At 180k miles, it was using a quart every 500 miles. When I started using the used Mobil One as make up oil, it would increase to 750 miles per quart as the ratio of used synthetic increased. That went on until the engine quit at 306k miles.

Synthetics are supposed to increase your gas mileage, but I’ve never been able to measure the increase. Certain tires are also supposed to increase your fuel economy too but I haven’t been able to measure that either.

Since synthetic lubricant is superior to mineral oil, and far less expensive overall, why would anyone opt to not use it? If it’s good for super-priced cars, then it’s good for lesser-priced vehicles. It has superior heat protection and does not break down as does mineral oil, so, your statement is not logical. Why would anyone argue with logic, anyway? With 15,000 mile lubricant, that means 1 lubricant change and 1 filter change in 15,000 miles. With 3,000 mile mineral oil that’s 5 changes and 5 filters in the same 15,000 miles - way more expensive to go the natural route. I would rather go with my years of experience with the superior quality synthetic lubricant, Mobil 1, and the scientists who work with it. It has characteristics far superior to mineral oil and the facts can be found at Mobil’s website. Synthetic lubricant is for all engines and wallets, esp in this economy. As I said, those who haven’t tried it speak from a no-knowledge base. Can’t argue with success. The engineers and scientists make a better argument because their product performs as advertised.It’s vastly superior and costs much less than mineral oil. And, again, when we use synthetics, we depend less on foreign govts who don’t like us. And, old fish, why would you switch to synthetic without researching it beforehand?

Mobil 1 turned to sludge after 3,000 miles? Hohohahaheehee.

None of the above.
Class III synthetic is highly refined Class II (standard) petroleum oil. Most “Synthetics” are Class III. Class IV are true synthetics. Mobil 1 and Royal Purple for example. Mobil 1 began as petroleum oil and has been molecularly modified into synthetic, meaning not found naturally. Class V synthetics were never petroleum based. Red Line for example. Auto makers don’t give additional mileage between changes for synthetic. Synthetics offer high heat tolerance and some auto makers specify esp those with turbos. Buy to suit but oil changes per mfg recommendation.

I own two vehicles and one gets synthetic oil and the other gets regular oil.

The Mazda turbo gets the synthetic oil because of the turbo, the heat generated, and because of the turbo it gets driven harder. (Can’t help it.) So the synthetic oil is more stable under these conditions.

The Nissan pickup just gets regular oil. This is a simple two wheel drive four cylinder vehicle. The way this vehicle is driven doesn’t warrant the use of synthetic oil.

The oil and filter in both these vehicles get changed at the 4,000 mile mark. That’s because when I look in the owners manual of either of these vehicles, niether of the manufacturer make any distinction between synthetic oil or regular oil and oil change intervals.

I look at synthetic oils as application specific. If you’re towing with the vehicle, or if the vehicle is exposed to extreme temperature conditions, or if you race the vehicle, or if the vehicle has a turbocharger and is driven hard, those are excellent applications. If I don’t see an application, I use regular oil.


Since synthetic lubricant is superior to mineral oil in many ways, and far less expensive overall,

Far less expensive??? Or do you mean it is less expensive per mile? Don’t assume it is a good idea to change oil less often than recommended just because you switched to synthetic. You don’t get longer oil changes just by changing oil type.

I really don’t think it was the result of Mobil 1, but rather what happened before you changed. Likely the Mobil 1 started cleaning things up and that is why you found the sludge that was already there.

I Use Synthetic Oil In Our GM Cars Because The Manufacturer Recommends It For The Extreme Cold Temperatures (Below Zero F) That Are Common Here For Much Of The Winter.

As you point out they specify synthetic, but not longer change intervals. Also, they recommend synthetic, but not a different viscosity than what they ordinarily recommend for conventional oil at extrerme cold temperatures.